2-substituted-2,2-dinitroethoxy-fumaric acid bis(2-substituted-2,2-dinitroethyl)ester

ABSTRACT

Compounds of the formula   WHERE X and Y vary independently and are F, H, NO2 and CH3 are prepared by reacting an alcohol of the formula   WITH DIMETHYL ACETYLENEDICARBOXYLIC ACID TO YIELD   WHICH IS THEN CONVERTED TO THE DESIRED PRODUCT. The compounds are useful as plasticizers in explosive and propellant compositions.

limited States Patent Marcus 11 3,872,159 Mar. 18, 1975 i 1 2-SUBSTITUTED-Z,Z-DINITROETHOXY- F UMARIC ACID BlS(2-SUBSTITUTED-2,2-DINITRO- ETHYL)ESTER [75] inventor: Henry J. Marcus, West Covina,

Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

Primary Examiner-Leland A. Sebastian Attornqv, Agent, or Firm-R. S. Sciascia; J. A. Cooke [57] ABSTRACT Compounds of the formula U y-c-cn -o-c-co ca c-x I I 110 r0 2 x c-ca-o c-ca where X and Y vary independently and are F, H, N0 and CH are prepared by reacting an alcohol of the formula y-c-cn on 2 with dimethyl acetylenedicarboxylic acid to yield Y ?-CH2-O-C co cn H3602; ca

which is then converted to the desired product. The compounds are useful as plasticizers in explosive and propellant compositions.

4 Claims, N0 Drawings BACKGROUND OF THE INVENTION This invention relates generally to plasticizers and more particularly to high energy carboxylic acid esters and to a process for the preparation thereof.

The use of plasticizers in both explosive and propellant compositions is widely known. There has long been a search for plasticizers which besides being thermally stable have a relatively high energy which can be released on detonation so that the propellant or explosive composition will have maximum energy per unit weight. It is also often desirable to have plasticizers which are miscible with other plasticizers so that mixtures of plasticizers can be used in a composition. The use of such mixtures will yield a product with a lower melting point than any of the components individually and will therefore enhance low-temperature properties olthe system.

SUMMARY OF THE INVENTION Accordingly. it is an object of this invention to provide high energy, thermally stable esters of fumaric acid.

Another object of this invention is to provide plasticizers which can be used in propellant and explosive compositions.

Still another object of this invention is to provide a method for the preparation of esters of fumaric acid.

Another object of this invention is to provide chemical intermediates which can be used to prepare esters of fumaric acid which are useful as plasticizers in propellant and explosive compositions.

These and other objects of the invention are accomplished by providing compounds of the formula l i 5 Y-cca o-c-co ca c-x x ccn o c-cn fi z where X and Y vary independently and arevselected from the group consisting of F, H, N0 and CH which are prepared by esterifying acids of the formula by any of the conventional esterification techniques.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The esters of fumaric acid are prepared. for example. according to the following reaction sequence:

co as no no I 2 3 I 2 0 2 c Y c ca on YCCH2-0-CO62 ca II! I 2 l 3 c no n0 K C CH OH Eolyphoaphozic acid a y-c-m -o-c-co cm c-x II I (or immner) The desired fumaric acid esters of this invention are obtained by a multi-step synthesis. First, dimethyl acetylenedicarboxylate is reacted with an alcohol of the formula a-c-w on where Y represents F, H, N0 and CH in pyridine and a solvent such as methylene chloride at about 0-5C for about 1 hour to produce Y-cca occo ca which is obtained afteraconventional work-up comprising washing. drying. filtering, and distilling. This eocl Pyridine y-c-cu occo cn c-x 0 ll CIMCCH m (or tamer) A]. c1 it c m on m a 2 2 -ccn o co cn c-x B I N02 m c cn o ccia product is then converted to the diacid by refluxing in water with HCl, followed by filtering. chilling and recrystallizing.

The diacid is then converted to the monoester by reacting the diacid with an alcohol of the formula X-C C8 03 The general nature of the invention having been set forth. the following examples are presented as specific illustrations thereof. It will be understood that the invention is not limited to these specific examples but is susceptible to various modifications that will be recognized by one of ordinary skill in the art.

EXAMPLE l DIMETHYL a( 2-FLUORO-2.Z-DINITROETHOXY) FUMARATE To a solution of 7.9g (0.] mole) of pyridine in 75 ml of methylene chloride was added dropwise at 3-5C with stirring and cooling over a period of min. a mixture of 7.7g (0.05 mole) of Z-lluoro-2.2-dinitroethanol and 7.lg (0.05 mole) of dimethyl acetylenedicarboxylate. A mildly exothermic reaction was observed and the reaction mixture turned deep orange-red with the color gradually intensifying. The reaction mixture was kept at 0-5C for an additional 60 minutes and then was washed with a cold solution of l lg of sulfuric acid in 50 ml of water. The methylene chloride solution was dried. filtered. concentrated and the residual material was degassed at 85C/0.l mm to give 14.3g of dark viscous oil. An analytical sample of material was obtained by distillation in a molecular still at lO()l05C/5O u. The distillate solidified at room temperature into a white solid mp. 42-44C. The product was dimethyl 2-fluoro 2.2-dinitroethoxyfumarate.

EXAMPLE 2 iZ-FLl ORO2.2-DlNlTROETHOXY) FUMARIC AClD A l liter flask was charged with 300 ml concentrated hydrochloric acid, 300 ml water and 87g dimethyl 01(2- tluoro l. Z-dinitroethoxy) fumarate. The mixture was stirred magnetically and heated in an oil bath at or near reflux for 4 hours. The hot mixture was filtered through filtcr-aid to remove some black decomposition prodacts. The filtrate was chilled at C for 1 hour. and the product separated by filtration and washed with cold 6N HCl. The filtrate was concentrated to a volume of I75 ml. 50 ml concentrated HCl was added, and following storage at 20C an additional 14.5g of acid was isolated. Total yield 425g. 28g of crude acid was dissolved with heating in 100 ml water. treated with decolorizing charcoal. filtered through filter-aid, and precipitated by additional of 100 ml concentrated HCl followed by cooling. The colorless solid melted at l94-5( EXAMPLE 3 MONO (2-FLUORO'ZJ-DINITROETHYL) ESTER OF a-t Z-FLUORO-Z. Z-DINITROETHOXY FUMARIC ACID a-(Z-Fluoro-Z.Z-dinitroethoxy) fumaric acid (l.l5g, 0.0043 mole and 5.5g polyphosphoric acid in a ml flask were immersed in an oil bath at 90C. In portions. Z-iluoro-Z.Z-dinitroethanol (1.9g, 95?! pure; 0.0117

molel was added with essentially no exotherm. The oil be further purified either by recrystallization from chloroform carbon tetrachloride, or by solution in sodium bicarbonate followed by filtration and acidification.

EXAMPLE 4 BlS(2-FLUORO-2,2-DlNlTROETI-IYL) ESTER OF 0d 2-FLUORO-2.Z-DlNITROETHOX Y) FUMARIC ACID A Acid Chloride Two grams (0.005 mole) of the mono-ester. purified by base-acid repreeipitation. were partly dissolved by heating in 22 ml chloroform (kept over calcium chloride). At 45C, 2.4g thionyl chloride was added with no indication of any reaction. At 30C, 10 drops of pyridine were added and the mixture heated to reflux for 4 hours. Homogeneity was never obtained.

The mixture was cooled to room temperature and filtered through filter aid to remove a very small quantity of brown particles. The solvent and excess thionyl chloride were removed under vacuum, leaving the product as a dark brown, viscous residue.

B. Esterification The crude acid chloride from above was dissolved in 10 ml methylene chloride and 1.23g 2-iluoro-2,2- dinitroethanol (about 0.008 mole) and a spatula-tip of anhydrus aluminum chloride were added. The mixture was refluxed for 4 /2 hours. After cooling, insolubles were removed with filter-aid and the filtrate washed with 5% aqueous sodium bicarbonate and then with water. The solution was dried briefly over silica gel. and the solvent removed under vacuum. ultimately for l0-l5 minutes at 40C/0.lmm. The residue. a viscous brown oil, was stored in the freezer. A few crystals appeared after 2 days. and these were saved as seeds. The main batch was dissolved in l0 ml toluene. giving a clear. light yellow solution. The addition of 4.5 ml cyclohexane caused a small precipitate of dirty appearance which was filtered off. A further portion ofcyclohexane (2.5 ml) was added. followed by seed crystals. The mixture was stored overnight in the freezer and the product filtered and washed, first with cold solvent mixture, then with hexane at 20C. The dried product consisted of nearly colorless crystals; weight 086g; m.p. 634C.

Similarly when esters of the general formula I l Y-e ca oc-co cn e-x xc o con wherein X and Y are other than F, are desired the appropriate alcohol in the above reactions may be used to obtain them.

Obviously numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

7 8 What is claimed as new and desired to be secured by 2. contacting in solution the product of step 1 with Letters Patent of the United States is: HCl to produce 1. A fumaric acid ester of the formula 80 i t: s z YCCH CCO CH -C-X' lU mfi 5926 CH x c 03 2 3. contacting in solution the product ofstep I with an alcohol of the formula 2 wherein X and Y vary independently and are selected 9 2 from the group consisting of F. H N0 and CH 2. A compound according to claim 1 wherein X and Y both represent F.

x-c-m om 3. A method of preparing the compounds of claim 1 2O 2 comprising;

1. contacting in solution dimethyl acetylenedicarhoxylic acid with an alcohol of the formula in the Presence of P yp p acid to Field lhfi mono ester of the product of step 2; g 4. contacting in solution the mono ester ofstep 3 ith thionyl chloride in the presence of pyridine to ob- Y 2 9H tain the mono ester mono acid chloride. and

5. contacting said mono ester mono acid chloride of g step 4 with an alcohol of the formula in the presence of pyridine at about 0-5C to promo duce a 2 x c (:5 on l Y-C: m oc-co cn 302 4. The process olclaim 3 wherein X and Y are both F. H 6 cm 40 x 

1. CONTACTING IN SOLUTION DIMETHYL ACETYLENEDICARBOXYLIC ACID WITH AN ALCOHOL OF THE FORMULA
 1. A FUMARIC ACID ESTER OF THE FORMULA
 2. CONTACTING IN SOLUTION THE PRODUCT OF STEP 1 WITH HC1 TO PRODUCE
 2. A compound according to claim 1 wherein X and Y both represent F.
 2. contacting in solution the product of step 1 with HCl to produce
 3. CONTACTING IN SOLUTION THE PPRODUCT OF STEP 2 WITH AN ALCOHOL OF THE FORMULA
 3. A METHOD OF PREPARING THE COMPOUNDS OF CLAIM 1 COMPRISING:
 4. The process of claim 3 wherein X and Y are both F.
 4. CONTACTING IN SOLUTION THE MONO ESTER OF STEP 3 WITH THIONYL CHLORIDE IN THE PRESENCE OF PYRIDINE TO OBTAIN THE MONO ESTER - MONO ACID CHLORIDE, AND
 4. contacting in solution the mono ester of step 3 with thionyl chloride in the presence of pyridine to obtain the mono ester -mono acid chloride, and
 5. contacting said mono ester - mono acid chloride of step 4 with an alcohol of the formula
 5. CONTACTING SAID MONO ESTER - MONO ACID CHLORIDE OF STEP 4 WITH AN ALCOHOL OF THE FORMULA 